Engine starting mechanism



Dec. 17, 1946. R. NARDONE v ENGINE STARTING MECHANISM Original Filed Oct 22, 1940 Pitta/ Ara Patented Dec. 17, 1946 orr cs ENGINE STARTING MECHANISM Romeo M. Nardone, Teaneclr, N. 3., assignor to Bendix Aviation Corporation, a corporation of Delaware Continuation of application Serial No.

October 22, 1940.

Teterboro, N. J.,

This application June 22,

1944, Serial No. 541,611

This invention relates to engine starting mechanism, and particularly to the parts which function to facilitate or produce engine engaging movement of the member which couples the en gine starter to the engine to be started.

An object of the invention is to provide an engine starter involving improvements in the starter structure; as, for example, in the structure which controls engagement of the starter with the engine.

A further object is to provide an engagement controlling mechanism, for an engine starter, characterized by improvements which reduce the number of parts requiring separate assembly and adjustment.

Another object is to provide an engagement controlling mechanism, for an engine starter, characterized by improvements which increase the torque transmitting surface area at the point where motion translation occurs during the engine engaging action.

While the invention is shown in the accompanying drawing as applied to a starter having torque transmitting mechanism of the type shown in Lansing Patent No. 1,962,397, it is not limited to such an application, nor are there any limitations as to the physical appearance of the elements in which the invention may be embodied,

except in so far as the appended claims uniformly recite such limitations. The drawing, therefore, merely illustrates the currently preferred mode of 9 Glaims. (Cl. 14-7) putting the invention into use; said drawing ineluding:

Fig. 1, which is a central sectional view of a starter to which the invention is applicable;

Fig. 2, whichis a perspective view of the screw element of the motion translating mechanism of .1:

Fig. 3 is a sectional view on line 3-3 of Fig. 2;

Fig. 4 is an-end view of Fig. 2;

Fig. 5, which is a sectional view of the cooperating shell, or nut, element of the motion translatingmechanism; and

Fig. 61s an end view of Fig. 5.

The starter, as'lllustrated in the drawing, includes a housing constituted by an inner section 3, an intermediate section 4, an outer section B.

and a plurality of screws 8 for detachably conmeeting said sections. The inner section 3 is provided with a flange i to receive bolts 8 for securing the starter to the crank case of an engine, a portion of the latter being indicated at 9. Secured to the section. are the field coils of an electric motor it having an armature shaft ll whose outer end is received in bearings i2 and whose inner end is received in a sleeve bear.- ing it which is supported in the transverse wall it of a barrel it that is rotatably received in houslng section 3. Adjacent the reduced portion of the armature shaft there is formed a pinion it that meshes with a planetary gear set which operates to drivably connect armature shaft l l with the barrel it, to rotate the latter in synchronism with rotation of the motor armature, but at considerably reduced speed; there being a double speed reduction by reason of the use of two complete planetary sets of gearing, in series relationship, but with a single outer gear ll serving as the orbit gear for both sets of planet pinionsthe higher speed set of planets including the planet l8 and two additional planets (not shown) and the lower speed set including the planet 3| and two additional planets (not shown). The

planet pinions 3| are mounted on shafts 32 which extend into, and therefore cause corresponding rotation of, the aforesaid barrel l5. Planets l8 are mounted on similar solid cylindrical members which extend into, and therefore cause corresponding rotation of planet race It surrounding sleeve bearing l3 and having a centrally extending toothed portion constituting a sun gear adapted to mesh and drive the planets 3i A multiple disk clutch 40 includes disks splined to the inner surface of barrel l5, with the remainder being splined to the outer surface of an interiorly threaded nut 4|. Resilient .means,

such as a plurality of coil springs M and an adjusting nut 13, are provided for varying the pressure with which disks Ml are maintained in engagement, as in the Lansing patent above identified.

Mounted for rotary and longitudinal movement within nut M is a threaded shaft 64 which is longitudinally spiined at its inner end to drivably engage a correspondingly splined, tubular and outwardly extending portion 38a of the law clutch member 38. According to former practice, the screw-shaft Ml would have a stop-nut threaded to its rear surface, such as stop-nut it of the Lansing patent above identified; but the present invention involves the concept of eliminating such a stop-nut, and reconstructing said screw-shaft in such manner as to render it capable of performing the identical function heretofore performed by the additional stop-nut. Specifically, I enlarge the diameter of the internally threaded part 46 of the shell or nut ti sufficiently to permit the splined part 41 of screwshait 44 to pass through the right-hand end of the nut, and also pass. beyond the internally The movement, of member j 7 (through nut GI) to move rod 59, to the left, relative to,b'arrel 15. Spring 53 insures full enwill Yl cause of the smaller internal thread diameter a the drain of current on the battery or other 'had to be assembled in the opposit direction, be-

that prevented assembly from the right).- In

addition to enlarging the diameter ofthe.

threads as and- 4a oi the nut 4i and screw M,

respectively, I-also cut a groove 55 around the screw, and I begin from a blank having a diameter, at its right-hand end, that is considerably greater than the diameter of the finished threads 46 and 68. This permits formation of a head portion 5t extending from groove 49 to the end surface 5!, which head portion serves as a stop limiting movement of the screwprecisely as'rlces the separate stop-nut 35 of the Lansing patent,

but without resort to use of such an additional member. Moreover, since the stop-head he is integral with thescrew-shait, there is greater capacity to resist end thrust than in theformer type of motion translating mechanism.

When the motor is energized by closing the circuit thereto from asuitable source of power, rotation of the armature shaft is transmitted through. the three-stage reduction gearing ilsaid internally threaded means, the axial movelustrated, to barrel l5. Rotation of the latter is yieldingly transmitted throughclut'ch disks Ill to nut 4i.

Shaft 44 and jaw clutch member 38 to rotate in unison with nut H, but the rotation got-these two members is resisted by resilient metallic ring 51 which causes non-metallic brake element 58 to have frictional engagement with the hub of member 38. The resultant drag on clutch member 38 is effective to cause shaft 44 to move to theleft, as viewed in Fig. 1, compressing spring 53 and yieldingly moving jaw member 38 into full meshing engagementwith the corresponding engine member 39. When the gagement stop-head 5D abuts against the, and surfaces .52 (see Figs. 5 and 6) of the threads 46 of nut ll. Engin member 39, clutch member 38, and shaft 44 now rotate in unison with nut, 38 is, effective g'agement of the jaw clutch members.

- Th electric motor is now eifectiveto crank the engine, and the inertia of the parts of the latteris gradually overcome. Relative rotation source of power. The friction clutch permits the use of relativelylight gears, protects the apparatus against bacmre, and permits the engine crankshaft to be brought up to speed gradually without a substantial decrease in'the speed of the motor armature. r

This application is a. continuation of my appllcation Serial No. 362,272, filed October 22, mo.

. What is claimed is:

i. For use in an engine starter, an axially mov-, able substantially cylindrical member of integral construction, one end of which is formed with a head portion of large diameter while the other end of relatively small diameter is centrally apertured, helical means disposed about a portion of said member intermediate said ends, a second portion of lesser diameter than the diameters of said head and helical portions and disposed between the latter to provide relative spacing therebetween, and internally threaded means engageable with said helical means to move said-cylindrical member axially in response to rotation of ment of said member in onerdirection being limited by engagement between the spaced head por-' tion and the, thread formation on said internally threaded means.

2. For use in an engine starter, an axially movable substantially cylindrical member of integral construction, one end of which is formed with a head portion of large diameter while the other end of relatively small diameter is centrally apertured; a. helical rib extending around a por tion of said'member intermediate said ends, .a

' second portion of lesser diameter than the diameters of said head and helical portions and disposed between the latter to provide .relative spacing therebetween, and internally threade means jaw clutch members are in complete meshing enbetween barrel IS-and jaw member 38 is permitted by-the. disk clutch 40 during the tim in:-

which the engine crankshaft is being brought up' to the speed of jaw 38.

the -s'peedof rotation of the crankshaft is greater thattliat'of jaw '38, The inclination of the teeth of 'jaw members 38 and 39 is now eflective to move member. .38 to the right out of driving ento the parts'will resultand the engine can never I When heengine starts under its own power,

engageable with said helical rib'to (we said cylindrical member axially in response to rotation of said internally threaded means, said internal- 1y threaded means also having a shoulder water) the axial travel of said cylindrical member when 'abutment occurs between said shoulder andthe spaced head portion of said-cylindrical member.

3; In an engine starter, an engine engaging 7 member, a driving member, and'means including a-motlon translating mechanism for translat ing the'initial rotation of said driving member '-into engine engaging movement of said engineengaging member, said motion translating mechanism including an internally threaded driving screw rotatableby said driving member, and a driven screw splined to the engine engaging member, said driven screw having .an' unthreaded portion integral therewith to provide a stop and movable into abutment with the ends of the threads of said screw to halt the motion translating action, the splined :portion of said,

driven screw being of relatively smaller diameter than the internally threaded portionof said driving screwso that the former may freely through the latter duringassembly.

drivelthe motor armature due to the construction 1 v,

- a motion translating mechanism for translating and-arrangement of the jaw clutch members. In

thelzvent the en iie'backfires, the'disk clutch dand no amage to the parts .wiliresult.

Theiaw clutch members 38 and are normally dis n aged; and energy is stored in the motor '4. In an engine starter, *an engine-engaging member, a driving member, and means including screw rotatable by said driving member, and a driven screw splined to the engine-engaging member, said driven screw having anunthread'ed portionfintegral therewith to provide a stop and movable into abutment with the ends of the threads of said driving screw to halt the motion translating action, said threads thereafter acting as splines to effect rotation of said driven screw and said engine engaging member, the splined portion of said driven s'crew being of relatively smaller diameter than the internally threaded portion of said driving screw so that the former may pass freely through the latter during assembly.

5. For use in an engine starter, an axially movable substantially cylindrical member of integral construction, one end of which is formed with a transverse end wall and adjacent unthreaded peripheral head portion of large diameter while the other end is formed with external splines of relatively small diameter; helical means disposed about a portion of said member intermediate said ends and of substantially the same diameter as the diameter of said peripheral head portion; a second unthreaded peripheral portion of lesser diameter than the diameter of said head and helical portions. said second portion being disposed between the head and. helical portions for spacing the same axially to provide a transverse shoulder on said head portion opposite .its endwall; and internally threaded means engageable with said helical portion to move said cylindrical member axially in response to rotation of said internally threaded means, the axial movement of said member in one direction being limited by engagement between said shoulder and said internally threaded means.

6. For use in an engine starter, an axially movable substantially cylindrical member of integral construction, one end of which is formed with a transverse end wall and adjacent unthreaded peripheral head portion of large diameter while the other end is formed with external splines of relatively small diameter; a helical rib extending around a portion of said member intermediate said ends; a second unthreaded peripheral portion of lesser diameter than'the diameters of said head and helical portions, said second portion being disposed between the head and helical portions for spacing the same axially to provide a transverse shoulder on said head portion opposite its end wall; and internally threaded means engag'eable with said helical rib to move said cylindrical member axially in response to rotation on said internally threaded means, said internally threaded means also having a shoulder to stop the axial travel of said cylindrical member when abutment occurs between the respective shoulders.

7. For use in an engine starter, an axially movable substantially cylindrical member of integral construction, one end of which is formed with a transverse end wall and adjacent unthreaded peripheral head portion of large diameter while the other end is formed with external splines of relatively small diameterrhelical means disposed about a portion of said member intermediate said ends and of substantially the same diameter as the diameter of said peripheral head,

portion; a second unthreaded peripheral portion of lesser diameter than the diameters of said head and helical portions, said second portion being disposed between the head and helical por-. tions for spacing the same axially to provide a transverse shoulder, on said head portion opposite its end wall; and internally threaded means engageable with said helical portion to move said cylindrical member axially in response to rotation of said internally threaded means, said internally threaded means also having a shoulder to stop the axial travel of said cylindrical member when-- abutment occurs between the respective shoulders.

8. For use in an-engine starter, an axially move able substantiallycylindrical member of integral construction, one end of which is formed, with a transverse end wall and adjacent unthreaded peripheral head portion of large'diaineter while the other end is formed with external splines of relatively small diameter; helical means disposed about a portion of said member intermediate said ends and of substantially the same diameter as the diameter of said peripheral head portion; a

second unthreaded peripheral portion of lesser engagement between said shoulder and said internally threaded means, said unthreaded peripheral portion of relatively small diameter being sufficiently smallerthan the threaded portion of said internally threaded means to afford free passage through the latter during assembly.

9. The combination in engine starting means,

of an axially stationary rotatable spline nut hav-- ing internal screw thread and an internal shoulder rearwardly of said thread, and a screw shaft having a portion ,insertible from the rear end of said nut forwardly-into said nut past said shoulder and said thread, a complemental externally shaft has been screwed forwardly in the nut a.

predetermined distance.

r ROMEO M. NARDONE. 

